1 Engine information - Weichai Groupen.weichai.com/.../201406/P020140625397636582224.docx · Web...

Document No.:WP7 EUVI Engine information WEICHAI POWER CO., LTD.

Repair & Maintenance Information Requirements (OBD)

1. Component and diagnosis information： Refer to Annex 1 "Component and diagnosis

information "

2. Diagnostic trouble codes：Refer to the file "Fault Code list and description "

3. Software calibration ID number applicable to a vehicle type：P_1434_EU6_EDC17

4. Information provided concerning proprietary tools and equipment4.1 EOL

Manufacturer: LAUNCH、WEICHAI

Type：WP-EOL100、WEOL

Function: The tools used for ECU data calibration and diagnosis when the vehicles roll off the production line.

Figure1 EOL made by LAUNCH

Figure2 EOL made by WEICHAI

4.2 Tester

Manufacturer: LAUNCH、WEICHAI


Type：WP-VDS100、"DIAGSMART"

Function: The tools used for reading fault information and maintenance on market service by service stations.

Figure3 Tester made by LAUNCH

Figure4 Tester made by WEICHAI

5. Data record information and two directional monitoring and test data 4S stores need to record the data information and two directional monitoring and test data, such as IUPR, the data tested by PMES and so on.


Vehicle OBD Information Requirements

1. The following information shall be made available to interested parties on a non-discriminatory basis: 1.1 Type and number of preconditioning cycles used during type approval: one hot WHTC1.2 Description of the type of OBD demonstration cycle used for type approval: cold WHTC & hot WHTC1.3 Comprehensive document containing the following in a tabulated form: i) Strategy for fault detection (fixed no. of cycles or statistical method) ii) List of OBD output codes and format used iii) Explanation of fault code data as requested in paragraph 2.3 for ISO 15765-4 and alternative protocols Refer to the file " Fault Code list and description "

2. Information regarding the manufacture of diagnostic tools:2.1 Communication protocol information as flow2.1.1 Additional protocol information to allow complete diagnosis in addition to 4.7.3 of

Annex 9B to UNECE Regulation 49：WWWHOBD follows ISO27145 protocol, Referred spec 27145-3 and 27145-22.1.2 Methods of obtaining and interpreting fault codes not in accordance with the 4.7.3 of

Annex 9B to UNECE Regulation 49：The DTCO format follows iso15031-6 protocol2.1.3 List of all available functional testsCurrent available function test :

Routine LiD Engine Test Type12 Detection of injector errors14 High pressure test15 Cylinder shut off test16 Run up test18 Compression test22 SCR complete test(quantity measurement and emptying)

2.1.4 Details of how to obtain all component and status information, time stamps, pending DTCs and freeze framesThe Read Data By Identifier service allows the client to request data record values from the


server identified by one or more data identifiers. regulate three mode.Mode1: This mode provide access to current emission relevant data value, inclanalog input ant outputs, digital input and output, as also system status information, The request to information acquires a DID that transfers the specific requested information to the on-board supply system. referred spec 27145-3 and 27145-2.The control units respond to this message by transferring the requested data value, which is most recently determined by the system. All returned data values for sensor readings are actual readings and not default or substitute values that are used by the system in case of an error.Mode6:This mode permits the access to the result of the on-board diagnostic /monitoring tests for specific components/systems.Mode9:This mode enable an external tester to query vehicle specific information like vehicle identification number(VIN), the Calibration Verification Numbers(CVNS)and calibration IDs(CALIDs).2.1.5 Location of diagnostic connector and connector detailsThe diagnostic connector is up to the standard of SAE J1962. It is located under the instrument panel at the driver’s left side, and is easily accessible from the driver’s seat.

3.Information on test and diagnosis of OBD-monitored components as follows:3.1 Compression test :The compression test is designed for the evaluation of both compression and expansion behavior of each cylinder in an engine. For this purpose the engine is cranked while the injections are switched off. During this cranking phase the durations for passing two freely applicable angle segments are measured for each cylinder. The calculation of the durations for each angle interval (in μs) is done in the ECU, the final evaluation and display of the results is done in the service tester. By calculating the difference of the two times per cylinder it is possible to judge the compression behavior accurately for each single cylinder.Test parameters:


3.2 Run up test:The run-up test (RunUpTst) is for the determination of the efficiency of single cylinders. The test is structured into two stages. In stage one a cylinder will be switched off over the diagnostic tester and the maximum speed will be measured, which is reached when adjustable number of segments is given. This happens at given positions of the boost-pressure actuator and the exhaust-gas recirculation and at given rail pressure and injection rate for the pre injection and main injection of the remaining active cylinders. In stage two all cylinders become switched off and the run down is controlled with an adjustable number


of segments. Over a comparison of these measured maximum speeds it’s possible to draw conclusions on the efficiency of the single cylinders.Test parameters:

3.3 High pressure test:In this test the set-point pressure is increased and relieved at four different engine speeds. At each step the pressure build-up and drop-down times are measured whilst injections are taking place normally. In a fifth step the engine speed from step four will be set again and the pressure drop-down time with injections switched off is measured. The determination of possibly faulty components is determined in a vehicle specific fault matrix via measured pressure build-up/drop-down times. The High Pressure Test is a service function which has no effect on normal driving. The test starts on demand by a diagnostic tester. All parameters of the test are stored in the data set. Alternatively it is possible that the parameters are handed over to the ECU by the tester. During the engine test the pressure characteristic is considered in a pressure build-up and a pressure reduction phase at up to four different engine speeds .The measuring point indicates the operating point that is active at the moment.Test parameters:Rail_tiUpHpTst[%], [%]=[0,...,3]Rail_stUpHpTst[%], [%]=[0,...,3]Rail_tiDwnHpTst[%] [%]=[0,...,6]Rail_stDwnHpTst[%] [%]=[0,...,4]


Annex 1 Component and diagnosis information

1.1 List and Purpose of All Components Monitored by the OBD System

The following chapter is designed to give an overview of the components monitored by the EOBD system. Its components and their functions within the whole system are described shortly.

Fuel System

High Pressure PumpThe High Pressure Pump is used to provide the high fuel pressure needed for direct diesel injection. The installed pump is a CPN2.2+ -type pump that always delivers maximum fuel quantity. It is fed by a gear Supply Pump with low pressure fuel.

Rail Pressure SensorThe Rail Pressure Sensor is used to determine the actual rail pressure. That value is needed for high pressure control, engine protection and injection control. The sensor is mounted to the rail. Solenoid Valve InjectorsThe Solenoid Valve Injectors are used to inject the desired fuel mass into the combustion chamber. They are mounted to the cylinder head centered above the combustion chamber.

Comprehensive Components Boost Pressure and Temperature Sensor

The Boost Pressure and Temperature Sensor are used to measure the air pressure and temperature after turbocharger and charge air cooler. The location of this measurement is on the intake manifold. These values are used to calculate the air fuel ratio by the ECU and the appropriate amount of fuel is calculated and injected to avoid extra black smoke occurs. Air Pressure Sensor

The Air Pressure Sensor is used to determine the atmospheric air pressure. This value is

needed when calculating the EGR set point, injection control. The sensor is located inside the

ECU.

Camshaft Sensor

The Camshaft Sensor is used to determine the top dead centre of the first cylinder. It is

mounted to the gear box.


Coolant Temperature Sensor

The Coolant Temperature Sensor is used to measure the temperature of the engine coolant.

This value is used for EGR control, and injection control. It is mounted to the thermostat.

Engine Speed Sensor

The Engine Speed Sensor is used to measure the engine speed. Moreover the measured

signal is needed to synchronize the engine together with the Camshaft Speed Sensor. The

sensor is installed at the crankcase.

EGR Cooler Downstream Temperature SensorThe EGR Cooler Downstream Temperature Sensor is used to measure the temperature of EGR cooler downstream. This value is used monitor the efficiency of the cooler. Charged Air Cooler Downstream Temperature SensorThe Charged Air Cooler Downstream Temperature Sensor is used to measure the temperature of Charged Air cooler downstream. This value is used for calculating the cooler efficiency. EGR Valve Position SensorThe EGR Valve Position Sensor is used to measure the position of EGR Valve. Throttle Valve Position SensorThe Throttle Valve Position Sensor is used to measure the position of Throttle Valve. HFM Sensor The HFM Sensor is used to measure the amount of the air mass flows into the engine. This signal is used for closed−loop control on the EGR valve.

DeNOx System

SCR Catalyst Upstream Temperature SensorSCR catalyst upstream temperature sensor is installed in exhaust pipe before catalyst. It is used to provide dew point detection of NOx sensor, control and correction of urea injection. Urea Heating Valve Urea heating valve is installed in heating pipe of coolant water. It is used to control heating of urea pipe from coolant water. NOx Sensor There are two NOx sensors used in the DeNOx system. One NOx sensor is installed in exhaust pipe after the turbocharger and before the HCI dosing unit. The other one is installed after catalyst. It is used to measure NOx concentration of exhaust. Urea Tank Temperature and Level SensorUrea tank temperature and level sensor is installed in urea tank. It is used to provide temperature and level of urea tank. Urea pump Temperature SensorUrea pump temperature sensor is installed in urea supply module. It is used to measure the


temperature of urea supply module. Urea Pressure SensorUrea pressure sensor is installed in supply module. It is used to measure pressure of urea. Pump Speed SensorPump speed sensor is installed in supply module. It is used to measure the rotating speed of the urea pump. Pump ActuatorPump actuator is installed in supply module. It is used to control the pressure of urea. Urea Dosing ValveUrea dosing valve is installed in exhaust pipe. It is used to inject urea to exhaust pipe. Environment Temperature SensorEnvironment temperature sensor is installed exposed in the air. It is used to measure environmental temperature.

DPM system

DOC upstream Temperature SensorDOC upstream temperature sensor is installed in exhaust pipe before the DOC. It is used to provide the exhaust temperature before DOC, and activation of HC injection. DPF upstream Temperature SensorDPF upstream temperature sensor is installed in exhaust pipe after the DOC and before the DPF. It is used to provide the exhaust temperature, and control for appropriate amount of diesel fuel injection when it is undergoing regeneration. DPF differential Pressure SensorThe DPF differential pressure sensor is installed in exhaust pipe before and after DPF. It is used to provide the exhaust pressure difference across the DPF. The measurement is used to estimate the soot load inside the DPF with a soot load model. DPM Upstream Temperature/pressure SensorThe sensor is integrated and installed in the metering unit before HC metering Valve. It is used to provide the fuel temperature and pressure. DPM Downstream pressure SensorThe sensor is integrated and installed in the metering unit after HC metering Valve. It is used to provide the fuel pressure downstream of HC dosing valve. HC metering ValveThe HC metering Valve is installed in the HC metering unit. It is used to measure the amount

of fuel for HC injection.

HC Shut-off ValveIt is used to control the on and off of the fuel flow to the dosing unit.

HC dosing unitIt is used to inject the fuel to the exhaust stream before DOC.


1.2 Description of OBD test principles and basic monitoring parameters

1.2.1 Description of error handling for the diesel engine

Fault diagnosis system is responsible for monitoring the engine control-related components

and control functions. Diagnosis system monitors electrical connection failures of the system

components, signals credibility and components measured value drift fault.

1.2.1.1 Fault storage

When fault diagnosis system has tested a component failure, the component is placed firstly

at "preliminary fault status."If the fault has been existed for a certain time (each component

has a time-to-defect), then it is placed at "confirmed defect status." If the fault disappears at

the time-to-defect, then the timer stops timing and reset to zero, if the fault occurs again,

the timer re-starts timing (figure 1). Fault recovery process and the fault test process is

similar (figure 2).

5.1 Fault test


5.2 Fault recovery

Entry state management


5.3 Entry state management

In order to operate vehicles safely and protect the engine and its components, some

measures to deal with the fault at "confirmed defect status" must be taken:

Measures to deal with the faults:

• The use of alternative values for certain variables

• Disable some functions

• Limit the range of variables

• Engine shutdown

Fault handling measures have been playing roles before the faults restore.


For different fault parts and fault type, fault information related to environment variables

may be set immediately or after setting driving cycles into the fault memory. General

diagnosis device can read out memory failure information and the environment variable

information from the fault memory. If the fault stored in the memory disappears at set

warm-up cycle, it will be deleted.

Because of limited memory size, memory can store limited fault information. When the fault

memory is full, and there are new fault storing request, the lowest priority fault information

will be replaced by the new one. If there are a lot of the lowest priority faults, the fault

information stored longest will be renewed.

1.2.1.2 Fault classification and Warning system

MIL activation modes

5.4 MIL activation modes


5.5 MI activation modes before engine start-1

MI activation modes before engine start

5.5 MI activation modes before engine start-2

MI activation modes after engine start


5.6 MI activation modes after engine start

MI Counters

1) Continuous MI on time (last activation)

Count while when MI is in mode “continuous”

Reset:

(1) Fault reoccurs after having been healed for 3 or more operation cycles

(2) Fault is erased via self deletion (40 Warm up cycles or 200h)or fault memory clear via

tester

2) Cumulative continuous MI on time (lifetime)

Count while: MI is in mode “continuous”

Reset: no reset

3) Class B1 fault counter *: Class B1 fault in state “confirmed and active”

Usage: for MI mode transition short continuous

Count while: Class B1 fault in state “confirmed and active” (MI switches on)

Reset:3 operation sequences without B1 fault (no reset via Tester)

Initialization: when B1 counter >= 200h AND no B1 fault in “confirmed and active” OR reset

via tester

Initialization Action: set B1 counter to 190h


Interaction when B1 counter >= 200h:

MI activation mode: transition short to continuous

MI counters: count for B1 fault also

MI behavior (engine on)

Activate MI (according activation mode):

(1) Fault is in state “confirmed and active”

(2) Malfunction emission control strategy (MECS) activated

Activation state changes *:

(1) B1 fault counter >=200h:

Transition: “short” to “continuous”

(2) Single positive test result (Class A and B1):

Transition: “continuous” to “short”

Deactivate MI: 3 successive operation sequences without fault

(* Engine on: visible in “discriminatory” display strategy only)Fault memory state

5.7Fault memory state

Part2 Degrade system

Degrade system include torque limit and vehicle limit.


5.8 inducement control overview

5.9inducement array


5.10 inducement state

5.11 inducement level bit

Activation conditions:

Wait with activation for stationary vehicle


5.12 inducement level1

Level 2: “Severe inducement”

vehicle creep mode (“disable vehicle”):

limit vehicle speed to 20 km/h

Reasons for activation:

- Same as for Stage1 but additionally

- Non heated SCR systems: no delivery due to frozen reagent (after 70 min)

Activation conditions

Options (use at least one), wait for:

- Engine restart (key off -> on) OR

- Fuelling (fuel tank level increase by measureable amount) OR

- Parking (stationary vehicle for > 1h)

and(mandatory):

- Disable on time limit (stationary after 8h engine operation)

5.12 inducement level1


1.2.2 Description of monitoring strategy for NOx emission monitoring and control system

OBD regulations requires that, any abnormal running of the engine related to NOx emission

control system should be monitored by the NOx sensor placed in the exhaust pipe. When

NOx emission is over 1.5g/kWh, the fault indicator is activated. When the fault time is over

10 hours , torque limiter start to work. When the fault time is over 20 hours , Vehicle speed

limiter start to work.

In cold WHTC cycle, hot WHTC cycle and the regeneration state, simulate the faults with the

total emission of 1.5g/kWh by using the deteriorated reactant, calculate separately

conversion efficiency limits at the corresponding conditions based on NOx concentration

measured.

At relatively stable conditions, the current average conversion efficiency limit is calculated

according to the NOx conversion efficiency limits at the corresponding conditions of total

1.5g/kWh emissions.

Average conversion efficiency limit=1-∫((1 minus conversion efficiency limit) NOx mass flow

upstream the catalyst)/∫NOx mass flow upstream the catalyst.

Actual average NOx conversion efficiency at present is calculated according to the actual

conditions and measured NOx concentration.

Actual average conversion efficiency =1-∫actual NOx mass flow downstream the catalyst

measured by the sensor/∫NOx mass flow upstream the catalyst.

If the actual average NOx conversion efficiency is lower than the average conversion

efficiency limit corresponding to the total 1.5g/kWh of NOx emissions, the system makes a

judgment that the actual NOx emissions exceeding emission limit of 1.5g/kWh.


Description of monitoring strategy for NOx emission monitoring and control system.

1.2.3 Diagnosis of fuel control unit

OBD system tests continuously and circularly the electrical connection faults of the fuel

control unit drive circuit. Faults include the short circuit to power supply, short circuit to

ground, open circuit and overheating fault.

Error test is conducted inside the drive circuit module. Diagnostic functions assess the

results of error test and handle the error.

N

Yes

Yes

N

No fault

Reset pre-integral

MI on and torque limiter Faultdetecte

Actual average NOx conversion efficiency lower the average conversion efficiency

MI activated

Actual average NOx conversion efficiency lower the average conversion efficiency limit corresponding to

End

Integrated above result and calculated average NOx

conversion efficiency and two

Stable

Integrated NOx conversion efficiency limit and actual

conversion efficiency

Exhaust gas flow calculated within the

normal range?

Yes

NOx density calculated upstream the catalyst

within the normal range?

Catalyst temperature within the normal

temperature range?

Start

N

No

No

Yes

Yes

Y

Fault


Test the battery short-circuit fault when the drive circuit is switched on: Monitoring the

actual output current of the drive circuit, if it exceeds the maximum limit, then short-circuit

to battery fault is detected; after that, the error is handled by the system diagnostic

function.

Test the ground short-circuit fault when the drive circuit is switched off: Monitoring the

actual output current of the drive circuit, if it exceeds the minimum limit, then short-circuit

to ground fault is detected; after that, the error is handled by the system diagnostic

function.

Test the open circuit fault when the drive circuit is switched off: Monitoring the actual

output current of the drive circuit, if it is within the preset range, then open circuit fault is

detected; after that, the error is handled by the system diagnostic function.

Test the overheating fault when the drive circuit is switched on: Monitoring the temperature

of the drive circuit parts, if it exceeds the temperature limit, then the error within the

module of the drive circuit is detected; after that, the error is handled by the system

diagnostic function.

Diagnosis flowchart for fuel control unit (drive circuit electrical fault)


No fault Fault handled and MI on

Fault detected

Fault detected

Fault detected

Fault detected

No fault detected

short circuit to ground?

Yes

No

Open circuit?

Yes

No

Short circuit to power supply?

Yes

No

Temperature too high?

Yes

No

Drive circuit switched on?

No

Yes

End

Start


1.2.4 Diagnosis of common rail pressure sensor

OBD system monitors continuously and circularly the output signal of common rail

pressure sensor: When the sensor output voltage signal exceeds the upper rated limit, short

circuit to power supply or open circuit is detected; When the signal is lower than the lower

limit, short circuit to ground fault is detected.

1.2.5 Diagnosis of pressure limit valve

OBD system monitors the open status of the pressure limit valve, the valve will be

opened compulsively when the following conditions occur:

When the rail pressure is higher than the upper limit, but valve has not been opened; or rail

pressure sensor goes wrong. In addition, the valve would be opened when it is blocked. If

the system detects an open valve, then the fault is of the max. type error; if system detects a

pressure lower than the lower limit, the fault is the min error; if the pressure limit valve is

not opened when the rail pressure is higher than the upper limit, the fault signal error is

detected.

OBD system also monitors the wear of the pressure limit valve. Once the pressure limit valve

is opened, the system will activate the timer and counter. Timer is used to cumulate open

time of the pressure limit valve, while counter is used for open times of the valves .Once the

timer exceeds the upper limit, then the min, type of error is detected. Once the counter

exceeds the upper limit, then the max, type of error is detected; If the timer and counter are

beyond the upper limits, then the signal type error is detected. The fault can’t be self

repaired, it can only be removed by the diagnostic device integrated with KWP2000 3B

protocol (reset timer and counter).

1.2.6 Diagnosis of water temperature sensor

OBD system monitors continuously and circularly the output signal of the cooling water

temperature sensor: When the sensor output voltage signal exceeds the upper limit, the

short circuit to power supply or open circuit fault is detected; When the signal is lower than

the lower limit, the short circuit to ground fault is detected.

1.2.7 Diagnosis of injector

Each cylinder injector and the drive circuit is detected once every working cycle. Electronic


injector control system controls the voltage on two ends of injector, charge and discharge

current solenoid valve with the help of the high and low side transistors.

Four injectors are controlled by a "column" module, the injector is controlled by a

specialized drive chip. The drive chip monitors the voltage at the both channels of the high

and low sides, charge and discharge current. If a deviation occurs compared with expected

voltage/current, then the fault is detected and transmitted to the micro-controller.

A mode recognition system is used to determine the fault more accurately (either for a

specific cylinder, specific module, or for the chip itself).In this mode recognition system, the

energizing time, the voltage, the current and the drive chip of each injector are all took as a

mode, compare this mode with the pre-defined error mode matrix, if more than a certain

number of cases conforming with pre-defined error pattern are detected, then the fault

corresponding to the error pattern is detected.


Injector diagnosis flowchart:

1.2.8 Diagnosis of atmospheric pressure sensor

OBD system tests the signal range of output voltage of the atmospheric pressure sensor.

If the output voltage signal of the sensor exceeds the upper limit, it indicates that the sensor

short circuit or open circuit to battery; if the sensor output signal is lower the lower limit,

then the sensor short circuit to ground.

No fault

Fault detected

Yes

Fault detected

Yes

No.

No.

Injector connection fault detected?

Injector drive chip fault detected?

No fault detected

Fault detected

Fault handled and MI on

There is failure for injector drive

control？Yes

No.

End

Start


1.2.9 Diagnosis of boosting pressure sensor

OBD system tests the signal range of output voltage of the boosting pressure sensor.

If the output voltage signal of the sensor exceeds the upper limit, it indicates that the sensor

short circuit or open circuit to battery; if the sensor output signal is lower than the lower

limit, then the sensor short circuit to ground.

1.2.10 Diagnosis of ECU modulus conversion module

OBD system tests the signal of ECU modulus conversion module. When the converter

reference voltage is higher than the upper limit calibrated, the largest type of fault is tested.

And when the converter reference voltage is lower than the lower limit calibrated, the

smallest type of fault is tested. When the converter test pulse voltage exceeds the upper

limit calibrated, signal type fault is tested; and when the converter signal is not converted

completely at certain time window, unauthentic type of fault is tested.

1.2.11 Diagnosis of ECU power supply module

OBD tests the voltage signal of ECU power supply module. When the voltage of the power

supply module is higher than the upper limit, the largest type of fault is tested. And when

the voltage is lower than the lower limit, the smallest type of fault is tested.

1.2.12 Diagnosis of fuel supply system

When the rail pressure controller operates at the state of closed loop controlling, the OBD

system tests the fault of fuel supply system by monitoring the controller deviation, the min.

rail pressure and the max. rail pressure.

The controller deviation includes plus deviation and minus deviation.

OBD can test two controller plus deviation faults. For the first deviation test, it makes a

comparison between the measured rail pressure deviation and the calculated limit according

to the engine speed. If the actual value is larger than the calculated value, then a fault is

tested.


For the second deviation test, two conditions must be met. First of all, the above described

first plus deviation fault must have been tested. Secondly, the fuel supply of fuel control unit

must be greater than one of the calibrated limits. When the above two conditions are met,

compare the deviation of rail pressure controller and one calibrated limit. If the deviation is

larger than the limit, then a fault is tested.

For test of controller minus deviation, the following conditions must be met: the fuel supply

of the control unit is lower than a calibrated limit, fuel temperature is higher than a

calibrated limit and injection quantity exceeds a calibrated limit. At this time, when the

deviation of rail pressure controller is lower than the calculated limit based on the engine

speed, then a minus deviation fault is tested.

When the rail pressure is lower than the calculated limit based on the engine speed, the

minimum rail pressure fault is tested.

When the rail pressure exceeds the calibrated limit, the maximum rail pressure fault is

tested.


Detecting flowchart for common rail pressure controller plus deviation (1):

Fault detected

No fault

No fault detected


End

Meeting all monitoring conditions?

No

Yes

Controller deviation over upper limit?

YesNo

Start


Detecting flowchart for rail pressure controller plus deviation (2):

No fault

Yes

No fault detected


End

Fault detected

Meeting all monit

N

Ye

Controller plus deviation j

Yes

Controller deviation

over

Yes

N

Fuel delivery

over

N

N

Start


Detecting flowchart for common rail pressure controller minus deviation:


End

Controller deviation less than

Yes

N

Fuel flow less than

limit

Meeting all monitoring co

N

Yes

Start

Yes

No fault detected

Fault detected

N


Detecting flowchart for rail pressure min/max limit:

1.2.13 Diagnosis of crankshaft sensor

The OBD system tests the output signal of crankshaft sensor for “no signal” or “unauthentic

signal”.

The crankshaft sensor is composed of a signal wheel and a Hall sensor. If the phase sensor

signal is effective, but there is no crankshaft sensor signal, then no crankshaft sensor signal

fault is tested.

The credibility of the signal is determined by testing the dynamic change of crankshaft signal.

When the dynamic change exceeds the stated engine speed limit, unauthentic signal fault is

No faultFault handled and MI on

End

No fault detected

Fault detected

Fault detected

Start

Common rail pressure less than

the min. value?

Yes

No 。

Common rail pressure over the

max. value?

Yes

No 。


tested.

The monitoring function is continually performed in engine operation.

1.2.14 Diagnosis of camshaft sensor

The OBD system tests the output signal of camshaft sensor for “no signal” or “unauthentic

signal”.

If the camshaft sensor signal is effective, but there is no camshaft sensor signal is tested,

then no camshaft sensor signal fault is tested.

If the camshaft sensor signal and the phase sensor signal failed synchronically, or there is an

improper angle deviation between the crankshaft sensor signal and the camshaft sensor

signal in engine operation, then unauthentic phase sensor signal is tested.

The monitoring function is continually performed in engine operation.

1.2.15 Diagnosis of EGR valve position sensor

OBD system monitors continuously and circularly the output signal of EGR valve position

sensor: When the sensor output voltage signal exceeds the upper rated limit, short circuit to

power supply or open circuit is detected; When the signal is lower than the lower limit, short

circuit to ground fault is detected.

1.2.16 Diagnosis of Throttle Valve position sensor

OBD system monitors continuously and circularly the output signal of throttle valve position

sensor: When the sensor output voltage signal exceeds the upper rated limit, short circuit to

power supply or open circuit is detected; When the signal is lower than the lower limit, short

circuit to ground fault is detected.

1.2.17 Diagnosis of EGR Cooler Downstream Temperature Sensor

OBD system monitors continuously and circularly the output signal of EGR Cooler

Downstream Temperature Sensor: When the sensor output voltage signal exceeds the upper

rated limit, short circuit to power supply or open circuit is detected; When the signal is lower

than the lower limit, short circuit to ground fault is detected.

OBD system monitors continuously and circularly the output physical signal of EGR Cooler

Downstream Temperature Sensor: When the sensor output physical signal exceeds the


upper rated limit, physical range check high error is detected; When the physical signal is

lower than the lower limit, a physical range check low error is detected.

1.2.18 Diagnosis of HFM Sensor

OBD system monitors the output signal of HFM Sensor: When the sensor output time signal

exceeds the upper rated limit, a "maximum value exceeded" is detected; When the signal is

lower than the lower limit, a "minimum raw value fallen short of" is detected.

The supply voltage BattU_u is continuously monitored to check whether it is in the

permissible limit defined by the application parameters. If the supply voltage exceeds these

thresholds, an error of supply voltage is detected.

1.2.19 Diagnosis of Charge Air Cooler Efficiency Monitoring

The temperature upstream of the Charge air cooler is calculated via an air system model.

The temperature downstream of the coolant temperature are measured via sensors. If the

efficiency calculated from these temperatures is less than a given threshold value, the

Charge Air cooler is detected as defective.


1.2.20 Diagnosis of EGR Cooler Efficiency Monitoring

The temperature upstream of the EGR cooler is calculated via an on−board air system

model. The temperature downstream of the coolant temperature are measured via sensors.

If the efficiency calculated from these temperatures is less than a given threshold value, the

EGR cooler is detected as defective.

1.2.21 Diagnosis of urea tank temperature sensor

This diagnostic function tests the voltage signal range of urea tank temperature sensor.

When the voltage signal of the sensor is higher than the calibrated upper limit, sensor short


End

defective cooler ?

Yes

N

Meeting all monit

N

Start

Yes

No fault detected

Fault detected

N


circuit to power is tested. When the signal is lower than the lower limit, sensor to ground

short circuit is tested.

1.2.22 Urea level sensor and remaining urea test

Diagnostic function monitors circularly the range of the output voltage signal of the urea

level sensor.

When the sensor output voltage signal exceeds the upper limit, short circuit to power supply

is detected; when the signal is lower than the lower limit, short circuit to ground is detected.

According to the OBD regulations, the remaining urea in the urea tank should be tested.

The remaining urea test is divided into 3 level. If remaining urea is lower than the first level,

then storage is error, but MI is not activated and urea injecting continuously. If remaining

urea is lower than the second level, MI is activated and urea injection is stopped, but the

urea is cooled continuously. If the remaining urea is lower than the third level, that is urea

tank is empty, then MI is immediately activated, at the same time the urea injection and

cooling is stopped.

Diagnosis flowchart for urea level sensor:



Fault detected

Fault detected

No fault detecteddetected

Sensor volt signal less than lower

Yes

No

Sensor volt signal over upper limit?

Yes

No

Urea volume sensor

mounted?

No

Yes

End

Start


Urea volume detecting flowchart:

1.2.23 Diagnosis for temperature sensor of urea supply module

The diagnosis function performs the range check of voltage signal sent from

temperature sensor of the urea supply module.

The short circuit to power supply would be detected when the voltage signals from sensor

got above the rated upper limit; the short circuit to ground would be detected when the

voltage signals got below the rated lower limit.

Fault detected

Fault detected


Fault detecteddetected

Remaining up to1st grade: urea adding?

Yes

No

Remaining up to 2nd grade:

injection Yes

No

Remaining up to 3rd grade: tank emptied?

No

Yes

End

Start

No


Whereas the urea solution will freeze when the temperature is below -11℃, the system

has urea solution heating function. If the urea temperature measured by the urea supply

module is less than the rated lower limit or more than the rated upper limit during urea

solution heating, the signal is not plausible.

1.2.24 Diagnosis for sensor power supply control module of after-treatment control unit

The sensor power is supplied by power supply control module. One power supply

control module can supply power for four sensors.

The power supply control module chip CY310 has self-diagnosis function. At the time of

fault handling, the error report self-diagnosed from power supply control module chip is

sent to after-treatment control unit, the final reaction corresponds with related sensor error

path.

1.2.25 Diagnosis for urea pressure pump

In the DeNOx system, the urea pump of supply module is used to increase the pressure

of urea solution. The pump adopts closed loop mode to control urea pressure in supply

module.

The pump speed can be calculated by measuring the operation of pump transmission shaft

with three Hall sensors. According to the measured values from three Hall sensors, the faults

of the pump can be detected, such as pump motor blocked, over speed for pump, Hall

sensor failure.

1.2.26 Diagnosis for urea injection valve

The urea injection valve adopts PWM wave control and is used to control the injection of

urea. The faults of urea control valve include short circuit to ground, short circuit to power

supply, open circuit, injector blocked.

The short circuit to ground and to power supply can be detected by the feedback

values of urea injection valve pins. The system inspects the feedback values of pins several

times, if the times of relevant feedback value setting is more than rated times, the system

reports the related faults. Under the condition of urea valve with its power on, if the PWM

wave controlled by injection valve is over the rated value, namely there is a request for

injecting urea; but the feedback voltage of the injection valve is less than the working limit,


namely there’s no action of the injection valve, the open fault then can be detected.

The plausibility of urea injection quantity and pump speed would be confirmed every time

in the course of system starting. The system evaluates the pump speed in accordance with

urea injection. If the urea injection quantity has a large change, but the pump speed has a

small change, then the fault of injector blocked should be detected.

Diagnosis flow chart for urea injection valve (short circuit to ground and to power supply)

Diagnosis flow chart for open circuit

No faultFault handled or MI on

SCG fault detecteddetected

SCB fault detecteddetected


Has injection valve pin P3.6 been set or reached the count

value?

Y

N

Has injection valve pin P3.3 been set or reached the count

value?

Y

N

End

Start


NDuty cycle more than the limit value？

the injection valve operate

in working scope?

Y

Start

No fault

injection valve voltage less

than rated lower limit?

End

N

Fault handled or MI on

Fault detecteddetected


Y

N

Y


Diagnosis flow chart for injector blocked

No

N

Y

Fault detected


Y

No fault

No fault detected

End

the change of pump speed more than

rated value in a certain period？

the change of urea injection quantity

more than rated value in a certain period?

Start


1.22 Diagnosis for urea pressure sensor and its plausibility

The diagnosis function performs the range check of voltage signal sent from urea

pressure sensor circularly.

The short circuit to power supply would be detected when the voltage signals from

sensor got above the rated upper limit; the short circuit to ground would be detected when

the voltage signals got below the rated lower limit.

The plausibility of urea pressure sensor should be inspected before urea pressure

increased in the course of system starting. The system compares the urea pressure with the

atmospheric pressure, if the difference is too large, then the fault can be detected.

1.2.27 Diagnosis for CAN and CAN communication

The system inspects the short circuit for CAN 1 and 2, CAN system hardware will report

related error when short circuit on High Side to Low Side of CAN 1 or 2 occurs.

The system inspects the message AMB and EEC1 for CAN, when the frame is detected

for time-out, effective message is overridden and J1939 message range stands in error, the

system can report error.

1.2.28 Diagnosis for urea heater valve

In winter, the system heats urea tank through introducing engine cooling water. The

cooling water is controlled with urea tank heater valve. Once the temperature reaches a

certain level, the urea tank heater valve will turn off. If the valve blocked, the urea tank

temperature would be too high due to the cooling water heating the urea tank continuously.

1.2.29 Diagnosis for NOx sensor

NOx sensor is in communication with after-treatment control unit through CAN, the

communication is as follows: the heating signal transferred from after-treatment control

unit to NOx sensor, or NOx value transferred from NOx sensor to after-treatment system.

The system determines the connecting faults of NOx sensor by the messages from CAN.

The faults include short circuit, open circuit, unreasonable supply voltage for sensor, NOx

signal above the Max. credible value of NOx.

The system determines the NOx heater signal faults by the messages from CAN. The


faults include shirt circuit and open circuit.

The NOx sensor operates around 800℃. The NOx heater starts heating the NOx sensor

after dew-point inspection. The system would inspect the sensor plausibility during NOx

sensor heating. If Max. heating time was over the time limit and no temperature signal came

from NOx sensor, the system would detect plausibility of heating.

Plausibility inspection for NOx sensor:

The inspections for NOx sensor plausibility include peak value inspection and

unreasonable signal change-range inspection. In this way, the plausibility NOx sensor signal

can be detected, as well as avoid using fake NOx sensor.

When the NOx flow rises from one steady-state to another before catalyst, NOx density

measured by NOx sensor should appear a wave peak after a certain period.

Wave peak inspection:

When the NOx flow rises from one steady-state to another before catalyst, the system

records the NOx density before changing. A min. change limit can be calculated by recorded

NOx density adding a theoretic change-value (calculated from catalyst temperature). After a

certain time delay, compare the min. change limit with the current NOx density measured by

NOx sensor, when measured density is less than min. change limit, NOx sensor signal peak

error can be detected.

Unreasonable signal change-range inspection:

When the NOx flow rises from one steady-state to another before catalyst, the system

records the NOx density before changing. After a certain time delay, compare the current

NOx density measured by NOx sensor with the former recorded value, when absolute value

of the difference is less than a certain value, the system determines that the signal of NOx

sensor is not plausible.

Diagnosis flow chart for connection fault of NOx sensor


Y

N

Y

N

N

Y

N

Y

End

Fault handled and MI on No fault

Fault detectedNo fault detected

downstream signal more than the max. probable

value of NOx？

sensor supply voltage

reasonable？

NOx sensor short circuit or open circuit?

CAN message transmission

normal?

Start


Diagnosis flow chart for signal fault of NOx heater

Start heating and timing after dew-point

inspection

N

Y

N

Y

N

Y

End

Fault handled or MI onNo fault


Receive the temp. signal from NOx

sensor after heating time over time limit？

NOx heater short circuit or open circuit?

CAN message transmission

normal?

Start


Diagnosis flow chart for peak value fault of NOx sensor

Delay timing and record NOx density measured by NOx

sensor

measure current NOx density and calculate min. change limit after a

certain time delay

N

N

Y

Y是

End


No faultFault detected

No fault detected

Current NOx density measured more than min. change limit?

NOx flow rises from one stead-state to another

before catalyst?

Start


Diagnosis flow chart for unreasonable signal range of NOx sensor

1.2.30 Diagnosis of SCR upstream temperature sensor

This diagnostic function tests the voltage signal range of SCR upstream temperature sensor.



Delay timing and record NOx density measured by NOx sensor

Current NOx density measured and min. change limit calculated after a certain time

delay

N

N

Y

Y

End

Fault handled and MI onNo fault


Absolute value of the difference more

than a certain value？

NOx flow rises from one stead-state to another before catalyst??

Start



1.2.31 Diagnosis of DPF upstream temperature sensor

This diagnostic function tests the voltage signal range of DPF upstream temperature sensor.




1.2.32 Diagnosis of DOC upstream temperature sensor

This diagnostic function tests the voltage signal range of DOC upstream temperature sensor.




1.2.33 Diagnosis of DPM upstream temperature sensor

This diagnostic function tests the voltage signal range of DPM upstream temperature sensor.




1.2.34 Diagnosis of DPM upstream pressure sensor

This diagnostic function tests the voltage signal range of DPM upstream pressure sensor.




1.2.35 Diagnosis of DPM downstream pressure sensor

This diagnostic function tests the voltage signal range of DPM downstream pressure sensor.




1.2.36 Diagnosis of DPF pressure difference sensor

This diagnostic function tests the voltage signal range of DPF pressure difference sensor.





1.2.37 Diagnosis for HC dosing valve

The HC dosing valve adopts PWM wave control and is used to control the injection of HC.

The faults of HC dosing valve include short circuit to ground, short circuit to power supply,

open circuit, valve blocked.

The short circuit to ground and to power supply can be detected by the feedback

values of HC dosing valve pins. The system inspects the feedback values of pins several

times, if the times of relevant feedback value setting is more than rated times, the system

reports the related faults. Under the condition of HC dosing with its power on, if the PWM

wave controlled by HC dosing valve is over the rated value, namely there is a request for HC

injection; but the feedback voltage of the injection valve is less than the working limit,

namely there’s no action of the dosing valve, the open fault then can be detected.

The plausibility of HC dosing valve would be confirmed every time in the course of system

starting. The system evaluates the HC pressure. If the value has a large difference from the

calibrated threshold，then the fault of dosing valve blocked should be detected.


Diagnosis flow chart for HC dosing valve (short circuit to ground and to power supply)

No faultFault handled or MI on

Has the valve pin been set or reached the count value?

Has the valve pin been set or reached the count value?

SCG fault detecteddetected

SCB fault detecteddetected

No fault detected

Y

N

Y

N

End

Start


Diagnosis flow chart for open circuit


the feedback signal smaller than the limit value?

the feedback signal larger than the limit value?

the valve operated in working state?

N

N

Fault detected

No fault detected

Y

N

Y

Y

Start

No fault

End


Diagnosis flow chart for valve blocked

1.2.38 Diagnosis for HC shut-off valve

The HC shut-off valve adopts PWM wave control and is used to control the injection of HC.

The faults of HC shut-off valve include short circuit to ground, short circuit to power supply,

open circuit, valve blocked. The logic of the valve faults detected is similar to HC dosing

valve.


No

N

Y

Fault detected

Y

No fault

No fault detected

End

Is the fuel pressure in the calibrated threshold？

Is there a system test for the HCI system？

Start


1.2.39 Diagnosis for HC injection valve

The HC injection valve is a mechanical valve. The fault of HC injection valve is blocked. The

logic of the valve blocked detected is similar to HC dosing valve.

1.2.40 Urea quality monitoring

OBD system monitors the Urea quality. When the urea quality is detected to have problem,

when NOx emission is over 0.9g/kWh, the fault indicator is activated. When the fault time is

over 10 hours , torque limiter start to work. When the fault time is over 20 hours , Vehicle

speed limiter start to work.

In hot WHTC cycle，simulate the faults with the emission of 0.9g/kWh by adding water to

urea, calculate the conversion efficiency limits at the corresponding conditions based on

NOx concentration measured.

At relatively stable conditions, the current average conversion efficiency limit is calculated

according to the NOx conversion efficiency limits at the corresponding conditions of 0.9

g/kWh emissions.

Average conversion efficiency limit=1-∫((1 minus conversion efficiency limit) NOx mass flow

upstream the catalyst)/∫NOx mass flow upstream the catalyst.

Actual average NOx conversion efficiency at present is calculated according to the actual

conditions and measured NOx concentration.

Actual average conversion efficiency =1-∫actual NOx mass flow downstream the catalyst

measured by the sensor/∫NOx mass flow upstream the catalyst.

If the actual average NOx conversion efficiency is lower than the average conversion

efficiency limit corresponding to the total 0.9 g/kWh of NOx emissions, the system makes a

judgment that the actual NOx emissions exceeding emission limit of 0.9 g/kWh.

1 Engine information - Weichai Groupen.weichai.com/.../201406/P020140625397636582224.docx · Web...

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